Use released versions of plugins

Author: Graeme Rocher

grails-bom/plugins.properties

@@ -1,7 +1,7 @@
 hibernate=4.3.5.5.BUILD-SNAPSHOT
 mongodb=4.0.0.BUILD-SNAPSHOT
-cache=3.0.0-SNAPSHOT
-asset-pipeline=2.0.0-SNAPSHOT
-scaffolding=3.0.0-SNAPSHOT
-fields=2.0.0-SNAPSHOT
-geb=1.0-SNAPSHOT
+cache=3.0.0.M1
+asset-pipeline=3.0.0.M1
+scaffolding=3.0.0.M1
+fields=2.0.0.M1
+geb=1.0.0.M1